<template>
	<view class="u-wrap">
		<view>
			<u-tabs-swiper :bar-height="70" :bar-width="180" :bar-style="{backgroundColor:'#20cbd4'}" 
				bg-color="#f6f6f6" active-color="#fff" inactive-color="#20cbd4"
				:list="sectionList" :current="sectionCurrent" @change="sectionChange" 
				:is-scroll="false"></u-tabs-swiper> 
		</view>
		<empty v-if="isEmpty1" :emptyImg="emptyImg" :emptyTxt="emptyTxt"></empty>
		<view class="u-menu-wrap" v-if="!isEmpty1">
			<scroll-view scroll-y scroll-with-animation class="u-tab-view menu-scroll-view" :scroll-top="scrollTop">
				<view v-for="(item,index) in classifyList" :key="index" class="u-tab-item" :class="[current==index ? 'u-tab-item-active' : '']"
				 :data-current="index" @tap.stop="swichMenu(index,item)">
					<text class="u-line-1">{{item.cate_name}}</text>
				</view>
			</scroll-view>
			<empty v-if="isEmpty" style="background-color: rgb(250, 250, 250);width: 140%;" :emptyImg="emptyImg" :emptyTxt="emptyTxt"></empty>
			<block v-if="!isEmpty" v-for="(item,index) in classifyList" :key="index">
				<scroll-view scroll-y class="right-box" v-if="current==index" @scrolltolower="buttom">
					<view class="page-view">
						<view class="class-item">
							<view class="item-title">
								<text>{{item.cate_name}}</text>
							</view>
							<view class="item-container">
								<view class="thumb-box" v-for="(item1, index1) in goodsList" :key="index1" @click="jumpPage(item1.goods_id)">
									<image class="item-menu-image" :src="item1.goods_image" mode=""></image>
									<view class="goodsInfo">
										<view class="item-menu-name u-line-2">{{item1.goods_name}}</view>
										<view class="price_box">
											<view class="price" v-if="item1.q_id == '1'">¥{{item1.goods_sku.goods_price}}</view>
											<view class="price" v-else-if="item1.q_id == '2'">
												<view v-if="item1.goods_sku.points>0">¥{{item1.goods_sku.price}}+{{item1.goods_sku.points}}券</view>
												<view v-else>¥{{item1.goods_sku.price}}</view>
											</view>
											<view class="price" v-else-if="item1.q_id == '3'">
												<view v-if="item1.goods_sku.points>0">¥{{item1.goods_sku.price}}+{{item1.goods_sku.points}}券</view>
												<view v-else>¥{{item1.goods_sku.price}}</view>
											</view>
											<view class="price" v-else="item1.q_id == '4'">
												<view v-if="item1.goods_sku.points>0">¥{{item1.goods_sku.price}}+{{item1.goods_sku.points}}券</view>
												<view v-else>¥{{item1.goods_sku.price}}</view>
											</view>
											<view class="market_price" v-if="item1.q_id == '3'">¥{{item1.goods_sku.market_price}}</view>
											<view class="sales" v-if="item1.show_stock == 1">已售{{item1.goods_sales}}件</view>
										</view>
									</view>
								</view>
							</view>
							<u-loadmore :status="status" v-if="!isEmpty" color="#909399" :margin-top="20"/>
						</view>
					</view>
				</scroll-view>
			</block>
		</view>
	</view>
</template>
<script>
	import search from "@/components/public/search.vue";
	import empty from "@/components/public/empty.vue";
	import {categoryList,goodsList} from "@/common/api.js";
	export default {
		components: {
			search,
			empty
		},
		data() {
			return {
				scrollTop: 0, //tab标题的滚动条位置
				oldScrollTop: 0,
				current: 0, // 预设当前项的值
				menuHeight: 0, // 左边菜单的高度
				menuItemHeight: 0, // 左边菜单item的高度
				itemId: '', // 栏目右边scroll-view用于滚动的id
				tabbar: [],
				classifyList:[],//商品分类
				goodsList:[],//商品数据
				menuItemPos: [],
				arr: [],
				scrollRightTop: 0, // 右边栏目scroll-view的滚动条高度
				timer: null, // 定时器
				sectionList: [
					{
						name: '主推区'
					}, 
					{
						name: '优选区'
					},
					{
						name: '福利区'
					},
					// {
					// 	name: '超享区'
					// }
				],
				isEmpty1:false,
				isEmpty:false,
				emptyImg:getApp().globalData.imageUrl+"empty_goods.png",
				emptyTxt:"暂无商品",
				sectionCurrent: 0,
				status: 'loadmore',
				pageSize: 10,
				pageStart: 1,
				total:0,
				cate_id:0 ,//分类id
				isShow:true
			}
		},
		onShow() {
			let coupon_type = uni.getStorageSync('coupon_type')|| '';
			if(coupon_type == "0"){
				//从个人中心优惠券来
				this.sectionCurrent = 1;
				uni.setStorageSync('coupon_type', "");
			}
			
			this.goodsList = [];
			this.pageStart = 1;
			this.selectClassify();
		},
		onReachBottom() {
			
		},
		onTabItemTap(e){
		},
		onReady() {
			this.getMenuItemTop()
		},
		methods: {
			buttom(){
				console.log(this.total/(this.pageStart*this.pageSize))
				if(this.total/(this.pageStart*this.pageSize)>1){
					this.pageStart++;
					this.selectGoodsList();
				}else{
					this.status = 'nomore';
				}
			},
			jumpPage(id){
				uni.navigateTo({
				  url: '/goods/goodsDetail?goods_id='+id
				});
			},
			//点击顶部专区切换
			sectionChange(index) {
				this.isShow = false;
				this.sectionCurrent = index;
				this.classifyList=[];
				this.goodsList = [];
				this.pageStart = 1;
				this.status='loadmore'
				this.selectClassify();
			},
			//查询商品分类
			selectClassify(){
				categoryList(this,{q_id:this.sectionCurrent+1});
			},
			//查询商品列表
			selectGoodsList(){
				goodsList(this,{page:this.pageStart,limit:this.pageSize,q_id:this.sectionCurrent+1,cate_id:this.cate_id});
			},
			// 点击左边的栏目切换
			async swichMenu(index,item) {
				if(this.arr.length == 0) {
					await this.getMenuItemTop();
				}
				if (index == this.current) return;
				this.scrollRightTop = this.oldScrollTop;
				this.$nextTick(function(){
					this.scrollRightTop = this.arr[index];
					this.current = index;
					this.leftMenuStatus(index);
				})
				this.goodsList = [];
				this.pageStart = 1;
				this.cate_id = item.id;
				this.selectGoodsList();
			},
			// 获取一个目标元素的高度
			getElRect(elClass, dataVal) {
				new Promise((resolve, reject) => {
					const query = uni.createSelectorQuery().in(this);
					query.select('.' + elClass).fields({
						size: true
					}, res => {
						// 如果节点尚未生成，res值为null，循环调用执行
						if (!res) {
							setTimeout(() => {
								this.getElRect(elClass);
							}, 10);
							return;
						}
						this[dataVal] = res.height;
						resolve();
					}).exec();
				})
			},
			// 观测元素相交状态
			async observer() {
				this.tabbar.map((val, index) => {
					let observer = uni.createIntersectionObserver(this);
					// 检测右边scroll-view的id为itemxx的元素与right-box的相交状态
					// 如果跟.right-box底部相交，就动态设置左边栏目的活动状态
					observer.relativeTo('.right-box', {
						top: 0
					}).observe('#item' + index, res => {
						if (res.intersectionRatio > 0) {
							let id = res.id.substring(4);
							this.leftMenuStatus(id);
						}
					})
				})
			},
			// 设置左边菜单的滚动状态
			async leftMenuStatus(index) {
				this.current = index;
				// 如果为0，意味着尚未初始化
				if (this.menuHeight == 0 || this.menuItemHeight == 0) {
					await this.getElRect('menu-scroll-view', 'menuHeight');
					await this.getElRect('u-tab-item', 'menuItemHeight');
				}
				// 将菜单活动item垂直居中
				this.scrollTop = index * this.menuItemHeight + this.menuItemHeight / 2 - this.menuHeight / 2;
			},
			// 获取右边菜单每个item到顶部的距离
			getMenuItemTop() {
				new Promise(resolve => {
					let selectorQuery = uni.createSelectorQuery();
					selectorQuery.selectAll('.class-item').boundingClientRect((rects) => {
						// 如果节点尚未生成，rects值为[](因为用selectAll，所以返回的是数组)，循环调用执行
						if(!rects.length) {
							setTimeout(() => {
								this.getMenuItemTop();
							}, 10);
							return ;
						}
						rects.forEach((rect) => {
							// 这里减去rects[0].top，是因为第一项顶部可能不是贴到导航栏(比如有个搜索框的情况)
							this.arr.push(rect.top - rects[0].top);
							resolve();
						})
					}).exec()
				})
			},
			// 右边菜单滚动
			async rightScroll(e) {
				this.oldScrollTop = e.detail.scrollTop;
				if(this.arr.length == 0) {
					await this.getMenuItemTop();
				}
				if(this.timer) return ;
				if(!this.menuHeight) {
					await this.getElRect('menu-scroll-view', 'menuHeight');
				}
				setTimeout(() => { // 节流
					this.timer = null;
					// scrollHeight为右边菜单垂直中点位置
					let scrollHeight = e.detail.scrollTop + this.menuHeight / 2;
					for (let i = 0; i < this.arr.length; i++) {
						let height1 = this.arr[i];
						let height2 = this.arr[i + 1];
						// 如果不存在height2，意味着数据循环已经到了最后一个，设置左边菜单为最后一项即可
						if (!height2 || scrollHeight >= height1 && scrollHeight < height2) {
							this.leftMenuStatus(i);
							return ;
						}
					}
				}, 10)
			}
		}
	}
</script>

<style lang="scss" scoped>
	.u-wrap {
		font-family: PingFang SC;
		height: calc(100vh);
		/* #ifdef H5 */
		height: calc(100vh - var(--window-top));
		/* #endif */
		display: flex;
		flex-direction: column;
	}
	.u-menu-wrap {
		flex: 1;
		display: flex;
		overflow: hidden;
	}

	.u-tab-view {
		width: 250rpx;
		height: 100%;
	}

	.u-tab-item {
		height: 90rpx;
		background: #f6f6f6;
		box-sizing: border-box;
		display: flex;
		align-items: center;
		justify-content: center;
		color: #4f3a1e;
		font-weight: 400;
		line-height: 1;
	}

	.u-tab-item-active {
		position: relative;
		color: #4f3a1e;
		font-size: 30rpx;
		font-weight: 600;
		background: #fff;
	}

	.u-tab-item-active::before {
		content: "";
		position: absolute;
		border-left: 4px solid #20cbd4;
		height: 90rpx;
		left: 0;
	}

	.u-tab-view {
		height: 100%;
	}

	.right-box {
		background-color: rgb(250, 250, 250);
	}

	.page-view {
		padding: 16rpx;
	}

	.class-item {
		margin-bottom: 30rpx;
		background-color: #f6f6f6;
		padding: 16rpx;
		border-radius: 8rpx;
	}

	.class-item:last-child {
		min-height: 100vh;
	}

	.item-title {
		font-size: 26rpx;
		color: $u-main-color;
		font-weight: bold;
	}
	.goodsInfo{
		display: flex;
		flex-direction: column;
		width: 360rpx;
	}
	.item-menu-name {
		font-weight: normal;
		color: $u-main-color;
	}

	.item-container {
		display: flex;
		flex-wrap: wrap;
	}

	.thumb-box {
		width: 100%;
		display: flex;
		margin-top: 20rpx;
		padding: 15rpx;
		border-radius: 10rpx;
		background-color: #fff;
	}

	.item-menu-image {
		width: 150rpx;
		height: 150rpx;
		margin-right: 15rpx;
	}
	.price_box{
		display: flex;
		// justify-content: space-between;
		align-items: flex-end;
		margin-top: 30rpx;
	}
	.price{
		color: #FA3534;
		font-size: 30rpx;
	}
	.market_price{
		font-size: 24rpx;
		line-height: 24rpx;
		color: #303133;
		margin-left: 16rpx;
		margin-bottom: 6rpx;
		text-decoration:line-through;
	}
	.sales{
		font-size: 24rpx;
		color: #909399;
	}
</style>
